Parts of a Flower - extension.umd.edu · 1/25/2017 Flowers 2 Parts of a Flower Stamen = anther + filament Pistil = stigma + style + ovary Petals (corolla) Sepals (calyx) Perianth

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Flowers

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Parts of a Flower

Stamen = anther + filament

Pistil = stigma + style + ovary

Petals (corolla)

Sepals (calyx)

Perianth =

calyx + corolla

Receptacle

Peduncle / Pedicel

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Flower Parts

Receptacle

Stamens

TepalsPistil

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Complete vs. Incomplete

Complete

having all parts sepals, petals, stamens, and a pistil or pistils

Incomplete

flowers lacking one or more of the “parts”

FothergillaYoshino Cherry

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Perfect flower

Having both functional stamens and pistils

Examples: Rose, Crabapple, Cherry, and Tuliptree.

Rosa moyesii

‘Neveda’

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Sterile flowers

Barren, not able to produce seed.

Examples: Many of the double flowering cultivars.

Viburnum plicatum

Japanese Snowball

Viburnum plicatum var.

tomentosum

Doublefile Viburnum

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Quiz time

Complete or Incomplete

Floral parts Complete or Perfect or

Present Incomplete Imperfect

S + P + St. + Pistil

S + St. + Pistil

S + St. Incomplete Imperfect

Incomplete Perfect

Complete Perfect

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Types of Ovary Position

Superior Hypogynous

Half-inferior Perigynous

Inferior Epigynous

Ex. Peach Ex. Cherry Ex. Apple

Receptacle

Hypanthium

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Types of Ovary Position

Superior - The superior ovary of the pistil is above the site of attachment of other floral parts (stamens, sepals, & petals)

Inferior - The inferior ovary is below the site of attachment of other floral parts

Half-inferior - These are flowers that show varying degrees of ovary position

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Inferior Ovary - Apple

Perianth tube

An apple develops from the

flower’s perinath tube.

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Petal-like

structures

Bracts

Poinsettia & Dogwood

Tepals

Tulip & Magnolia

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Nectar Guides - pollination

Iris Foxglove

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Inflorescences

Spike. The flowers

are attached to the stem without stalks (no peduncle).

Acanthus sp.Crabgrass

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Inflorescences

Raceme. The

flowers are attached to the stem by short stalks (pediuncle).

Sweet Broom

Genista racemosa

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Inflorescences

Panicle. The

flowers are attached on pedicels on a main axis called the peduncle, which is an extension of the stem (peduncles & pedicels).

Begonia sp.

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Inflorescences

Umbel. The

flowers stalks arise from one point at the tip of a stem.

Agapanthus africanus

African Lily

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Inflorescences

Composite head.An inflorescence composed of many tightly packed, small flowers.

Out flowers - Ray

flowers (showy and sterile)

Inner flowers - Disc flowers (fertile flowers)

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Inflorescences

Solitary. Occurring

alone, not paired or clustered.

Rosa x ‘Voodoo’

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Monoecious - Separate male and

female flowers (cones) on the same plant

Male conesFemale cones

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Dioecious - Separate male and female

flowers (cones) on the different plants

Ginkgo Holly

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It just keeps going!

Polygamo-monoeciousrefers to condition where male, female and perfect flowers occur on the same plant.

Polygamo-dioecioushaving male and female flowers on separateplants, but these plants having perfect flowers as well.

MulberryRed Maple

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Quiz time

Which of these two flowers is capable of producing fruit and seed? A or B

Need

Both

A

B

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Reproductive Process

Pollination - The transfer of pollen from the stamen to the stigma.

Fertilization - The fusion of gametes

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Self-unfruitful/self-sterile

The pollen of the flowers of a single plant will not fertilize the pistils of the flowers of that plant. In other words, pollen from another plant of a different clone is necessary, or cross-fertilization is required.

Bradford Pear

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Parthenocarpy

(parthenocarpic)

Development of fruit without pollination, fertilization or seed development

Other examples Nellie R. Stevens Holly, Burford Holly, Banana, and most varieties of Figs (e.g., Brown Turkey

and Celeste)Nellie R. Stevens Holly

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Reasons plants stopped flowering

Insufficient light - decreasing light levels

overtime

Winter injury, late frost or wind (tissue

desiccation)

Drought / heat stress

Improper pruning

Lack of vigor

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Reasons plants stopped flowering -

cont....

Diseases, pests and injuries

Misuse of pesticide sprays

Leaf and flower buds may be killed or damaged by

spraying when temperatures are below 40oF

Over-spraying of dormant oil, lime sulfur and other

fungicides and insecticides may damage buds and

blooms

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Reasons plants fail to fruit

Plants only produce sterile flowers

Plants only produce male flowers

Plants need to be cross pollinated

Growing season is too short

Improper or lack of pruning

Pests e.g., squirrels, deer, etc.

Stress e.g., drought, borers

Plants that have never set fruit

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Plants that have stopped setting

fruit or have dropped fruit

Pollen source has be removed

Insufficient light

Improper or lack of pruning

Lack of vigor

High and low temperatures, e.g., kills pollen, inhibits

fertilization, and causes flowers to abort.

Drought stress, excessive water

Insufficient pollination, lack of insect pollinators

Plants that have stopped setting fruit

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Questions

Developed by Steve Dubik

Montgomery College

240-567-7803

[email protected]